I'm planning to only generate versions from 1.2, which is the first release we adopted a release branch for. I'm planning to only build documentation on the tip of each release branch (so, 1.2, 1.3, 1.4). I'm planning to cherry-pick the commits from this branch onto those three release branches.

To serve multiple versions of the docs, we're going to have an apache config along these lines:

# The default documentroot is 'current' aka master
DocumentRoot /var/www/doc.arvados.org/current/
# More human friendly name
Alias /master /var/www/doc.arvados.org/current
# The releases each get a directory, and these directories
# sit at the same level as the master directory. Map
# them correctly here.
RewriteEngine On
RewriteCond %{DOCUMENT_ROOT}/../%{REQUEST_URI} -d [OR]
RewriteCond %{DOCUMENT_ROOT}/../%{REQUEST_URI} -f
RewriteRule ^/(v\d.\d.\d.*)$ /var/www/doc.arvados.org/$1

This is the 'dev' part of the above issue description. I'm planning to do the other parts as an expansion of our existing git hook, there's no need for a jenkins task here.